docs: def start_move_player(self, move_name, speed=1.0, backwards=False):
          """Move player need to have a move file
          <move_name.record> in the working directory to play it"""
  
          # check if running
          try:
              player = getattr(self.robot, '_{}_player'.format(move_name))
              if player.running:
                  return
          except AttributeError:
              pass
  
          # if not running, override the play primitive
          with open('{}.record'.format(move_name)) as f:
              loaded_move = Move.load(f)
          player = MovePlayer(self.robot, loaded_move, play_speed=speed, backwards=backwards)
          self.robot.attach_primitive(player, '_{}_player'.format(move_name))
  
          player.start()
          return player.duration()